Many methods and processes are known to clean, purify, clarify and otherwise treat fluids for proper disposal, consumption, use, and other needs. These methods include, but are not necessarily limited to, centrifugation and filtration to remove particulates, chemical treatments to sterilize water, distillation to purify liquids, decanting to separate two phases of fluids, reverse osmosis to desalinate liquids, electrodialysis to desalinate liquids, pasteurization to sterilize foodstuffs, and catalytic processes to convert undesirable reactants into useful products. Each of these methods is well-suited for particular applications and typically a combination of methods is used for a final product.
There are many different known technologies available for the sterilization of liquid. Adsorption, chemical treatments, ozone disinfection, and ultraviolet (UV) irradiation all perform very well for the removal of pathogenic microbes. However, each of these technologies has limitations, including overall efficacy, initial capital cost, operating cost, byproduct risk, necessary pre-treatment of liquid, hazardous compounds used or produced, and which thus must be properly disposed of, and other limitations.
Although chemical methods are the most widespread in use, they have a number of shortcomings. Such drawbacks include increasing microbiological adaptation to their destructive effects, safety hazards associated with chlorine use and storage, and environmental impact. UV is a popular treatment, but the liquid must be clear in order for it to be effective, and it does not break down any biofilm formation; it is also very expensive to install and operate. In industrial and municipal applications such as water and wastewater plants, the three most widely used methods of liquid sterilization are ozone treatment, chlorine treatment, and UV irradiation.
Desalination of liquids is highly useful for drinking water, biological fluids, medicines, chemicals, petroleum and its derivatives, and many other liquids. In addition, desalination of water would be beneficial since less than 0.5% of the Earth's water is directly suitable for human consumption, agricultural, or industrial uses. Consequently, desalination is finding increasing favor to produce potable water from brackish groundwater and seawater since it makes the other approximately 99.5% of the water available. There are five basic desalination methods: thermal, reverse osmosis, electrodialysis, ion exchange, and freezing. Thermal and freezing processes remove fresh water from saline leaving behind concentrated brine. Reverse osmosis and electrodialysis employ membranes to separate salts from fresh water. Ion exchange involves passing salt water over resins which exchange more desirable ions for less desirable dissolved ions. Only thermal and reverse osmosis processes are currently commercially viable. Even so, these two methods tend to be prohibitive due to their expense.
There is always a need to develop new apparatus and methods that will help perform these methods and processes more cost effectively than their traditional counterparts. In the area of liquid purification, any technology that can lower the overall cost, simplify the process, and improve efficiencies would be very advantageous. It would thus be desirable if methods and/or structures would be devised to purify liquids, such as wastewater, using simple methods and devices.